It is crucial to be sure about the safety of nuclear facilities for human resources who are in danger of radioactive emission, also diminishing the volume of the wastes that are buried under the ground. Chemical decontamination of nuclear facilities can provide these demands at the same time by dissolving the oxide layer, which radionuclides such as 60Co and 58Co have been penetrated, of parts that are utilized in nuclear plants. Although there are many commercial methods to approaching its aim and they perform a high decontamination factor, they have some issues such as applying organic acids which have the ability to chelate with radionuclides that can be washed by underground water, have large quantities of radioactive waste and damage to the surface by severe intergranular attack. A new method has been introduced by KAERI’s scientist which is named the HyBRID Process, in this process the main solution is the acidic form of Hydrazine. In this process, like other acid-washing processes, there is a chance of corrosion on the metal surface which is not desired. The metal surface is able to be protected during dissolving process by adding some organic and inorganic corrosion inhibitors such as PP2 and PP3. There is a very new research topic about ionic liquids (ILs) as corrosion inhibitors which illustrates a vast potential for this application due to their tunable nature and the variety of options for cationic and anionic parts. The key factors for ILs corrosion inhibitors such as the hardness properties are summarized. In this study, we review to the fundamentals and development of corrosion inhibitors for chemical decontamination and give an prospect with emphasis on the challenges to be overcome.

The objectives of the present study were to investigate the effect of five chemical inhibitors on methane production of the pure cultures of methanogens. To examine the methanogenesis inhibition by 2-bromoethane sulfonic acid (BES), 3-bromopropane sulfonic acid (BPS), lumazine, propynoic acid and ethyl 2-butynoate, they were added into the pure cultures of Methanobacterium formicicum KOR-1 and KOR-12, Methanoculleus bourgensis KOR-2, Methanosarcina mazei KOR-3, KOR-7, KOR-9 and KOR-10, Methanosarcina vacuolata (DSM 1232), Methanobacterium bryantii (ATCC 33272), Methanosarcina mazei (ATCC BAA159) and Methanosarcina barkeri (ATCC 43240). Each methanogen was anaerobically incubated at 39℃ for 6 and 10 days, and then methane gas production was measured. All methanogens were sensitive to BES, lumazaine and ethyl 2-butynoate and as the addition levels of the chemicals increased, the methanogenesis was linearly reduced. BPS and propynoic acid failed to inhibit any of the methanogens. There were important differences among species of methanogens regarding their sensitivity to the different inhibitors. In general, the strains of Methanosarcina species were the most resistant to BES, lumazaine and ethyl 2-butynoate and the strains of Methanobacteriales order the least resistant. The different resistances to chemical inhibitors may be caused by different cell membrane structure, substrate utilization for methanogenesis and competition with other microorganisms for electron receptors. In conclusion, differences among methanogens habituating in anaerobic ecosystems, such as the rumen of ruminants regarding their resistance to chemical inhibitors should be considered when strategies of inhibition of methanogenesis are designed.